This is the entire timeline I made up for Mangled Memories. This is what I was originally basing my story off, things may have changed along with dates in the final product so sorry about that. This is mostly to clear things up a tad.

The bite of '87 happened along with the missing children incident, but only 2 kids were killed, this lead to the first location being shut down.

In this timeline there was only 2 locations, the first one (FNAF 2) and the second one (FNAF 1) where the story is based in (the building layout is different and is bigger and more improved due to there never being stress with budget, the pizzeria just ruled the killings off as a one off thing and they just put the animatronic that caused the bite away in storage, the storys were lost in history along with the first location).

The child killer never struck again and the 2nd building (where the story is based) was never shut down. In this story the child killer never got caught, the police had suspects but never arrested anyone.

This resulted in the 2 murdered kids taking vengeance, one possessed Vixey (causing the bite of '87) and the other one possessed Freddy (making him want to kill the night guards)

Timeline:

December 20th, 1980: The first location opened, the original owner being Phil, a designer and robotics technician who invented the animatronics and was working on the Free Will chip but he kept it a secret from the public, only the employees knew. He gave the job to Mr. MacDonald while he stayed back and went on with designing

May 1st, 1987: The purple guy killed the 2 kids at the location by luring them into the back of the restaurant saying he was an employee and promised them a special show from the animatronics

May 3rd, 1987: The kids souls were restless and wanted to find the killer, so they tagged along with the pizzeria convinced the killer was an employee like he said

May 28th, 1987: The first kid's soul possessed Vixey during a show causing the malfunction and resulting in Vixey killing the employee (Cameron's father)

June 1st,1988: The place shut down and around a year later a new one opened in New Athens and Phil took the job from Mr. MacDonald because he believed he didn't take good care of the animatronics at the previous location and gave the job to Mathew and the events of the old location were forgotten

June 3rd, 1988: Mathew took the old animatronics from the old location before they got scrapped and used them at the new restaurant to save money, he also took Vixey but left her in the storage after learning the events of the previous location, Vixey still had the spirit inside her that constantly mocked her over the 29 years, trying to get her to kill herself to allow itself to escape her body, Vixey just thought it was a voice in her head

October 28th, 1989: The second kid possessed Freddy at the new location convincing him kill the night guards and trying to find the killer who was long gone, the pizzeria kept it a secret and disposed of the bodies in the woods to try and save their reputation until the 'Glitch' in Freddy was fixed

December 12th, 1991: The police gave up the investigation into the missing children incident

January 23rd, 2013: The phone guy who left the messages to help the guards coming after him but got killed on night 4 and his body was stuffed in a suit in the back room where Cameron would later find it, the body was never found by police and they gave up the search a week later. The spirit of the man went on to possess the Golden Freddy suit he was stuffed in and became the spirit of Golden Freddy

March 14th, 2016: Mathew bought the old free will chips off Phil and used them in the animatronics

March 15th, 2016: The events of the current story took over